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유동방향 변화에 따른 고분자 전해질 연료전지의 성능 및 전달특성에 대한 3차원 수치해석적 연구
이필형,한상석,황상순,Lee, Pil-Hyong,Han, Sang-Seok,Hwang, Sang-Soon 한국전기화학회 2008 한국전기화학회지 Vol.11 No.1
Many researches for effects of different flow configurations on performance of Proton Exchange Membrane Fuel Cell have extensively been done but the effects of flow direction at the same flow channel shape should be considered for optimal operation of fuel cell as well. In this paper a numerical computational methode for simulating entire reactive flow fields including anode and cathode flow has been developed and the effects of different flow direction at parallel flow was studied. Pressure drop along the flow channel and density distribution of reactant and products and water transport, ion conductivity across the membrane and I-V performance are compared in terms of flow directions(co-flow or counter-flow) using above numerical simulation method. The results show that the performance under counter-flow condition is superior to that under co-flow condition due to higher reactant and water transport resulting to higher ion conductivity of membrane. 고분자 전해질 연료전지의 성능향상을 위한 방법으로 유동채널의 형상을 변경한 많은 연구가 진행되어 왔으나 동일한 유동채널 형상에서 유동방향 변경에 따른 연구는 많이 진행되지 못하였다. 본 연구에서는 동일한 반응면적과 동일한 유동채널의 고분자 전해질 연료전지의 수소와 산소의 유동방향을 Co-flow에서 Counter-flow로 변경될 경우의 연료전지의 성능변화를 분석하기 위하여 연료극과 공기극이 포함된 3차원 수치해석모델을 개발하였다. 개발된 수치해석모델을 활용하여 Co-flow와 Counter-flow의 유동채널 내부의 압력손실, 반응물질의 농도분포, 고분자 전해질 막을 통한 Water Transport, 고분자 전해질 막의 이온전도도 및 I-V 성능곡선을 비교하였다. 그 결과 반응물질의 농도분포, Water Transport, 고분자 전해질 막의 이온전도도가 우수한 Counter-flow 유동조건에서의 성능이 Co-flow 유동조건에 비하여 더욱 우수하였다.
평행류와 Interdigitated 유로를 가진 교분자 전해질 연료전지(PEMFC)의 성능특성에 대한 수치해석
이필형,조선아,최성훈,황상순,Lee, Pil-Hyong,Cho, Son-Ah,Choi, Seong-Hun,Hwang, Sang-Soon 한국전기화학회 2006 한국전기화학회지 Vol.9 No.4
고분자 전해질 연료전지의 분리판의 유동채널 설계는 고전류밀도에서 발생하는 농도분극에 직접적인 영향을 줄 뿐 아니라 생성되는 물의 효과적인 전달을 위하여 매우 중요하다. 평행류 유로와 interdigitated 유로의 성능비교를 위하여 연료극과 공기극이 포함된 완전한 형태의 고분자 전해질 연료전지의 3차원 수치해석모델을 개발하였다. 수치해석모델을 사용하여 평행류 유동장과 interdigitated 유동장의 압력강하, 채널간의 물질전달, $H_2O$와 $O_2$의 농도 분포 그리고 i-V 성능을 비교하였다. 그 결과 물질전달에서 채널간의 대류에 의한 물질전할이 더욱 우수한 interdigitated 유동채널에서 성능이 더 높게 나타났으며 압력강하는 보다 크게 나타나 설계시 두가지 성능에 대한 상호보완이 필요함을 알 수 있었다. Optimum design of flow channel in the separation plate of Proton Exchange Membrane Fuel Cell is very prerequisite to reduce concentration over potential at high current region and remove the water generated in cathode effectively. In this paper, fully 3 dimensional computational model which solves anode and cathode flow fields simultaneously is developed in order to compare the performance of fuel cell with parallel and interdigitated flow channels. Oxygen and water concentration and pressure drop are calculated and i-V performance characteristics are compared between flows with two flow channels. Results show that performance of fuel cell with interdigitated flow channel is hi민or than that with parallel flow channel at high current region because hydrogen and oxygen in interdigitated flow channel are transported to catalyst layer effectively due to strong convective transport through gas diffusion layer but pressure drop is larger than that in parallel flow channel. Therefore Trade-off between power gain and pressure loss should be considered in design of fuel cell with interdigitated flow channel.
유로형상 및 운전조건에 따른 고분자 전해질 연료전지의 성능 특성
이필형(Pil-Hyong Lee),조선아(Son-Ah Cho),한상석(Sang-Seok Han),황상순(Sang-Soon Hwang) 대한기계학회 2007 대한기계학회 춘추학술대회 Vol.2007 No.5
For proton exchange membrane fuel cell, it is very important to design the flow channel on separation plate optimally to maximize the current density at same electrochemical reaction surface and reduce the concentration polarization occurred at high current density. In this paper, three dimensional computation model including anode and cathode domain together was developed to examine effects of flow patterns and operation conditions such as humidity and operating temperature on performance of fuel cell. Results show that voltage at counter flow condition is higher than that at coflow condition in parallel and interdigitated flow pattern. And fuel cell with interdigitated flow pattern which has better mass transport by convection flow through gas diffusion layer has higher performance than with parallel flow pattern but its pressure drop is increased such that the trade off between performance and pressure drop should be considered for selection of flow pattern of fuel cell.
이필형(Pil Hyong Lee),이재영(Jae Young Lee),박창수(Chang Soo Park),박봉일(Bong Il Park),황상순(Sang Soon Hwang) 한국연소학회 2009 KOSCOSYMPOSIUM논문집 Vol.- No.38
Fuel processing systems which convert fuel into rich gas need high temperature environment. Generally, anode-off gas or mixture of anode-off gas and LNG used as input gas of fuel reformer. The purpose of this study is to develop a porous premixed flat ceramic burner that can be used for 1-5㎾ fuel cell reformer. Ceramic burner experiments using natural gas, hydrogen gas, anode-off gas were carried out respectively to investigate the flame stability characteristics by heating capacity and equivalence ratio. Results show that the stable flat flames can be established for natural gas, hydrogen gas, anode off gas and mixture of natural & anode off gas as reformer fuel in the porous ceramic burner. For all of fuels, their burning velocities become smaller as the equivalence ratio goes to the lean mixture ratio, and a lift-off occurs at lean limit. Flame length in hydrogen and anode off gas became longer with increasing the heat capacity. In particular, the blue surface flame is found to be very stable at a very lean equivalence ratio at heat capacity and different fuels.
Baffle Plate와 염공변화를 통한 평면 예혼합 원통형 다공철판 버너의 최적화 실험
이필형(Pil Hyong Lee),박봉일(Bong Il Park),박창수(Chang Soo Park),이재영(Jae Young Lee),황상순(Sang Soon Hwang),정은찬(Eun Chan Jeong) 한국연소학회 2009 KOSCOSYMPOSIUM논문집 Vol.- No.39
다공철판을 이용한 원통형버너는 내구성과 취성이 높고 가격이 낮아 많은 연구가 진행되고 있다. 본 논문에서는 많은 장점을 가지고 있는 원통형버너를 구성하는 분포판과 Baffle Plate의 재질과 형상을 변경하여 원통형 버너의 연소특성 및 배기가스 배출특성을 알아보았다. 연구결과 분포판의 재질이 Reference에서 청동소결, Mesh, 타공판 분포판으로 변경되면 다공원통형 버너의 화염이 심하게 떨리는 문제점이 해결됨을 확인하였다. 또한 염공의 경우 (a), (b), (d)의 염공은 독립화염을 형성하였고 (c)의 경우 1차원 평면화염을 형성하였다. 모든 염공에서 배기가스 측정결과 NOx의 경우 당량비 0.724-0.793 영역에서 약 13ppm이하의 NOx가 배출됨을 확인하였으며 (a)와 (d)의 경우 당량비 0.770-0.724 영역에서 50ppm 이하 의 CO가 배출됨을 확인하였다.
Perforated SiC 관 내부에서 초단열화염의 형성 및 개질에 대한 연구
이필형(Pil Hyong Lee),차천륜(Chun Loon Cha),홍성원(Seong Weon Hong),황상순(Sang Soon Hwang) 한국연소학회 2011 KOSCOSYMPOSIUM논문집 Vol.- No.43
Meso scale combustion process in the perforated silicon carbide (SiC) tube was numerically simulated for reforming methane to the syngas with GRI Mechanism 1.2. To verify the existence of super adiabatic flame, the combustion process under the equivalence ratio of mixture of 1.0 and inlet flow velocity of 60㎝/s was examined. Its result shows that the flame with temperature spike can be stabilized in a meso scale SiC tube reactor. And under operating conditions of rich equivalence ratio of 2.0 relevant to reforming process of methane, it was observed that the shape of flame temperature peak shows similar to that at equivalence ratio of 1.0. The position of flame temperature peak was moved to outlet region gradually with increasing the inlet velocity.
이필형(Pil Hyong Lee),박봉일(Bong Il Park),조순혜(Soon Hye Jo),황상순(Sang Soon Hwang) 한국연소학회 2010 한국연소학회지 Vol.15 No.3
Fuel processing systems which convert fuel into rich gas (such as stream reforming, partial oxidation, autothermal reforming) need high temperature environment (600~1,000℃). Generally, anode-off gas or mixture of anode-off gas and LNG is used as input gas of fuel reformer. In order to make efficient and low emission burner system for fuel reformer, it is necessary to elucidate the combustion and emission characteristic of fuel reformer burner. The purpose of this study is to develop a porous premixed flat ceramic burner that can be used for 1~5 ㎾ fuel cell reformer. Ceramic burner experiments using natural gas, hydrogen gas, anode off gas, mixture of natural gas & anode off gas were carried out respectively to investigate the flame characteristics by heating capacity and equivalence ratio. Results show that the stable flat flames can be established for natural gas, hydrogen gas, anode off gas and mixture of natural gas & anode off gas as reformer fuel in the porous ceramic burner. For all of fuels, their burning velocities become smaller as the equivalence ratio goes to the lean mixture ratio, and a lift-off occurs at lean limit. Flame length in hydrogen and anode off gas became longer with increasing the heat capacity. In particular, the blue surface flame is found to be very stable at a very lean equivalence ratio at heat capacity and different fuels. The exhausted NOx and CO measurement shows that the blue surface flame represents the lowest NOx and CO emissions since it remains very stable at a lean equivalence ratio.
니켈합금 Metal Foam을 적용한 예혼합 버너의 연소특성
이필형(Pil Hyong Lee),황상순(Sang Soon Hwang),김종광(Jong Kwang Kim) 한국연소학회 2017 한국연소학회지 Vol.22 No.2
A premixed combustion has many advantages including low NOx and CO emission, high thermal efficiency and a small volume of combustor. This study focused on combustion characteristics in a premixed combustion burner using the nickel based metal foam. The results show that the blue flame is found to be very stable at heating load 6,300-25,200 kcal/h by implementing the proper nickel based metal foam and baffle plate. The premixed flame mode is changed into green flame, red flame, blue flame and lift off flame with decreasing equivalence ratio. NOx emission was measured 80 ppm(0% oxygen base) from 0.710 to 0.810 of equivalence ratio and CO emission is 90 ppm(0% oxygen base) under the same equivalence ratio. It is also found that the stable blue flame region in flame stability curve becomes wider with increasing the heat load.